Mar 10, 2009

MORE THAN 99.9% OF ALL DOGS WILL NEVER ATTACK ANYBODY

Marjorie Darby, who ran the wonderful (and now unfortunately defunct) website, Goodpooch.com has one of those brains I like to pick. She's smart, logical and thorough. We sure miss her out here and wish she'd resurrect her site, but she's trying to have some fun these days so I'm not bugging about that. Much :>)

Anyway, somebody emailed me looking for the reasoning behind her statement that 99.9% of all dogs will never attack anybody. I asked her how she came up with the figure and in her usual gracious way, she responded in some detail. What follows is the explanation.

I hope you enjoy it and will pass it on.

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"Research
shows over 99.9% of all dogs, from all breeds, will never be involved in an
attack. Thus, I also like to say, “If any breed were genetically
programmed to attack, surely more than 0.1% of them would.”--Marjorie Darby

Back in 1999 or 2000, researcher Marjorie Darby looked at
news stories about dog bites, and separated them into what were reported to be
rather simple bites (ie, 'a pit bull looked at me') and those reported as being
more serious (ie resulting in more serious injuries - needing stitches,
hospitalization, surgery, etc.).

Ms Darby had a good contact at Toronto Humane Society at the time, who moved on
to Toronto Animal Services as an enforcement/investigation agent. When
queried about the number of dog bite cases, and the relative number of those
that were more serious than a simple bite she confirmed the general
ratio (nearly all reports were simple bites with minor injuries, only a tiny
number could be called "serious".) Based on all of this
information, it became clear that there were (and are) very few actual serious
dog bite cases in Canada.
There were maybe a dozen serious dog bite cases from across Canada in the
year studied.

To err on the side of caution, Darby decided to assume that the
real number of "attack" cases was double, triple or more compared with
what she had learned, since she didn't have (and no one has) access to the
precise number of incidents. As Janis Bradley says, nobody is counting
dog bites, you have to search hospital records for information - which only represent a portion of all bites.

Darby knew that many serious dog bite cases don't end up in
the media because of breed bias. Still, she could only confirm maybe a
dozen dog "attack" cases in Canada, nationwide, over a period of about
a year.

Not having access to every single dog attack case, she tried
to come up with a reasonable percentage to use in discussions about dog
attacks. With a dog population somewhere around 5,000,000 in Canada, 0.1%
is 5,000. That would mean that, in any given year, there would be 5,000
serious dog attacks, if just 0.1% of dogs were involved.

You can further extrapolate to come up with an even more
conservative statistic by theorizing a 10-year lifespan for dogs. It's
not a one-to-one ratio, but a simple way to do that is to simply divide by
10. That leaves the potential for 500 dog attacks per the entire lifespan
of every dog in Canada,
if just 0.1% of them were to do so. And based on what was found
concerning the the number of serious dog biting incidents, that is
still well within the range of the 0.1% figure (i.e.up to 500 attacks in any
given year). (Keep in mind that she only confirmed maybe a dozen or
so serious dog attacks in Canada that year - far fewer than the 500
figure.)

The process is the same for the U.S. but we have better
estimates about the number of 'pit bulls' there than here in Canada.

There are estimated to be about 65,000,000 dogs in the U.S.*
0.1% is 65,000. Meaning, in any given year, if 0.1% of American dogs
"attacked", there'd be 65,000 attacks, or 178 serious dog attacks
every, single day of the year. Not just bites, mind you, but
"attacks".

Hospital data vary greatly, but 800,000 dog bites treated
medically is at the extreme high end, and most of the data around 1999-2000
suggested the figure was more like 300,000 or 400,000. Still, that
doesn't tell us anything about severity, just that medical attention was sought.

Janis Bradley came on board and showed that fewer than 1% of
medically-treated dog bites score higher than a "1" (the lowest
ranking) in objective hospital injury recording criteria. Assuming the
dog "attacks" make up this 1%, that would mean about 4,000
biting incidents were more serious than a "1", if assuming
400,000 dog bites treated medically that year. 4,000 represents
0.006% of of the 65,000,000 dogs in America. If you want to do
the simple 10-year lifespan conversion, that would be 0.06% of all dogs at any
time in an average 10-year lifespan. That's still well-within the 0.1%
generalization. (It's almost half!)

There are estimated to be about 9 million 'pit bulls' in the
U.S.
Darby used a very conservative estimate of 5,000,000 to calculate what 0.1% of
'pit bulls' attacking would mean. It comes out to about 14 serious
attacks, every single day of the year. Every day that went by where there
weren't 14 serious 'pit bull' attacks somewhere in the U.S., that
would mean that even fewer than 0.1% of all 'pit bulls' were involved in a serious biting incident.
Given that 'pit bull' incidents are reported by the media at such a high rate,
I would be surprised to learn than so many serious 'pit bull' attacks
are being ignored by them, if it is to be alleged that more than 0.1% of 'pit
bulls' are attacking people.

You can do the 10-year lifespan calculations on an
estimated U.S.
'pit bull' population anywhere from 5 million to 9 million
individuals. None of the calculations suggest anything other than that
99.9% of dogs, or even 99.9% of all 'pit bulls' will NOT be involved in an
attack at any time in their lives.

'Pit Bull' Fatality
Data

"When it
comes to ‘pit bulls’, fewer than 0.1% will ever be involved in an attack at any
time in their lives, and even conservative estimates suggest at least 99.99998%
of all ‘pit bulls’ have not killed anyone."

When Darby was conducting this research in 1999-2003,
there had been approximately 80 human fatalities attributed to 'pit bull'
attacks in the previous 30 years or so in the U.S. 9,000,000 'pit bulls' (assuming
a 10 year lifespan) would easily translate into 27,000,000 'pit bulls' that
existed during that 30-year period. 80 fatalities out of 27,000,000 is
0.0002%.

While that seems incorrect to Darby, since she recalls at
some point, a few years ago confirming it was 4 zeros after the decimal,
rather than 3, that's what this calculation concludes. Nonetheless, we're
still talking about, at most, 0.0002% of 'pit bulls' having killed a person in
the U.S.
That leaves 99.9998% innocent of the allegation they're all killers.

When
we're talking about such small numbers, Darby would still have no problem
saying, "Frankly, I don't know what relevant information is gleaned
from the acts of less than 0.0002% of the population. Whatever it may be,
it certainly doesn't conclude anything about the rest.Again
I would also reiterate, if any breed were genetically-programmed to attack,
certainly more than 0.1% of them would".

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*According to the most recent US census results, there are now an estimated 72 million dogs in the United States.